The greater Baltimore area in Maryland has a large population of African-Americans and European-Americans, which makes this area most suitable to investigate differences in the exposure to prostate cancer risk factors among these two population groups. We designed a study that will use an integrated molecular epidemiology and translational research approach to examine causes for the excessive burden of prostate cancer among African-American men, including the study of tumor biological differences between African-American and European-American patients, supported by the collection of blood, urine, tissue samples, and survey data. Other epidemiological studies of prostate cancer have been established in recent years;however, only a few of these studies address the need for health disparity research and will have the opportunity to collect fresh-frozen tumor specimens from case subjects. Our study was implemented in two phases. The first phase, which started in April of 2005, constituted a pilot study to evaluate recruitment procedures. This phase was successful and the full study was initiated with minor changes to the protocol in April of 2006. Study participants will be African-American and European-American males who reside in Baltimore city and surrounding areas. The study will recruit 1000 prostate cancer cases and 1000 population-based controls, with recruitment ending in 2015. The cases are recruited at two Baltimore hospitals, the Veterans Affairs Medical Center and the University of Maryland Medical Center. Cases will have pathologically confirmed prostate cancer. The population-based controls are identified through the Maryland Department of Motor Vehicles database, and are frequency-matched by age and race to cases. The study involves the administration of two questionnaires and collection of blood and urine from all study subjects. Fresh-frozen tumor specimens will be obtained from cancer patients if available after prostatectomy. The study survey evaluates tobacco use, medication use, occupational history, diet, medical and sexual history, familial cancer history, and socioeconomic status. The study is supported by an epidemiological infrastructure that has been developed by our resource contractor at the University of Maryland for a lung cancer case-control study. This lung cancer study is ongoing, and the controls that are recruited for the prostate cancer study are joint controls with the lung cancer study. Hence, population-based male controls recruited by our contractor have double eligibility for the concurrent lung and prostate cancer studies. To achieve an age and race matching of cases and controls in the prostate study, we will over-sample for male controls in the lung cancer study. This study and the ongoing lung study are described by a recently established website at (http://home.ccr.cancer.gov/GEMES/index.html). The website also describes the policy for collaborations involving data sharing. Study protocol and the two questionnaires can be accessed at: http://www3.cancer.gov/intra/lhc/Ambs/Prostate_Cancer_Case_Control_Study_Protocol.pdf http://www3.cancer.gov/intra/lhc/Ambs/Lung_Prostate_Case_Control_Questionnaire.pdf http://www3.cancer.gov/intra/lhc/Ambs/Prostate_Cancer_Supplementary Questionnaire.pdf Our study is aimed at identifying candidate differences in risk factor exposure and tumor biology that exist among African-American and European-American men. We will also test the hypothesis that environmental and genetic factors contribute to the existing prostate cancer health disparity among African-Americans and European-Americans. Molecular work will be used to examine race/ethnic differences in tumor biology. Currently (September 2011), we have recruited about 695 cases (375 European-Americans and 320 African-Americans) and 357 population-based controls (214 European-Americans and 143 African-Americans) and we have collected blood and urine from these individuals. Future recruitment rates are set at 80 cases and 140 controls per year. The participation rate of eligible subjects has been very good and 85% of the eligible case patients and 80% of the eligible population-based controls enrolled into the study. Importantly, we had very similar participation rates for African-Americans and European-Americans. We have also collected paraffin-embedded and fresh-frozen tissue specimens for 89 tumors from prostatectomy surgery.